After graduating from the Massachusetts Institute of Technology in 1890, he worked in his family's chemical business until he left to join his cousin Coleman du Pont in his street railway business in 1899. To prevent the sale of the chemical business to outsiders, he joined cousins Coleman and Alfred du Pont in a buyout of the family firm, and became its treasurer, in which role he pioneered the use of return on assets and return on equity as methods of determining the financial well-being of a firm. After buying out Coleman's stake in the firm in 1914, and assumed the presidency until his retirement in 1919 to become president of General Motors (1920–23, chairman 1923–29). He spent his retirement years after 1929 tending his extensive gardens and donating millions to Delaware's public schools.